Pneumatic tool

ABSTRACT

A pneumatic tool comprises a housing, a chamber formed inside the housing, and a pneumatic mechanism and a cylinder disposed inside the chamber. The housing includes a gas inhale channel and a gas exhaust channel respectively interconnecting with the chamber. A ventilation gap is formed between the cylinder and chamber. The cylinder includes a compartment receiving the pneumatic mechanism, a gas inlet hole interconnecting with the compartment and gas inhale channel, and at least one gas outlet hole interconnecting with the compartment and ventilation gap. The pneumatic tool also comprises at least one buffer turbulent channel disposed on at least one of the sides of the cylinder and chamber, which face the ventilation gap. The variation of the cross section area between the ventilation gap and buffer turbulent channel can regulate flowing the speed of the high-pressure and high-speed gas and make it drive the pneumatic mechanism smooth.

FIELD OF THE INVENTION

The present invention relates to a pneumatic tool, particularly to a pneumatic tool using a buffer turbulent channel to make high-pressure and high-speed gas to flow smooth.

BACKGROUND OF THE INVENTION

A pneumatic grinder is a handheld tool driven pneumatically by compressed air to grind or polish the surface of a workpiece normally made of metal or wood. A Taiwan patent No. M295556 disclosed a pneumatic grinder, which comprises a housing, a cylinder, a transmission shaft, a grinding wheel, and a pneumatic wheel. The housing includes a chamber, an air incoming pipe and an air outgoing pipe. The air incoming pipe and the air outgoing pipe interconnect with the chamber. The cylinder is disposed inside the chamber, including an air cell whose sectional area is smaller than that of the chamber, an air inhale channel interconnecting with the air incoming pipe and the air cell, an air exhaust channel formed in the cylinder and interconnecting with the air cell and the chamber. The transmission shaft extends from the air cell to the exterior of the housing. The grinding wheel is disposed at one end of the transmission shaft, which is far away from the housing. The pneumatic wheel sleeves one end of the transmission shaft, which is inside the air cell. In application, a high-pressure and high-speed gas flows through air incoming pipe into the air cell to drive the pneumatic wheel to rotate. The pneumatic wheel further drives the grinding wheel to rotate through the transmission shaft. The user moves the rotating grinding wheel to contact the surface of an object, such as a metallic or wooden workpiece, to grind or polish the object. Next, the high-pressure and high-speed gas flows from the air cell through the air exhaust channel to the chamber (i.e. to the gap between the housing and the cylinder). Then, the gas flows from the chamber to the air outgoing pipe. Therefore, the pneumatic grinder continuously inhales and exhausts the high-pressure and high-speed gas to drive the grinding wheel to rotate and grind a workpiece.

While persistently flowing from the chamber to the air outgoing pipe, the high-pressure and high-speed gas is likely to clog in the air outgoing pipe and unlikely to exhaust. Thus, the high-pressure and high-speed gas is hard to go from the air incoming pipe to the air cell to drive the pneumatic wheel.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to solve the problem that the high-pressure and high-speed gas cannot smooth drive the pneumatic device to rotate in the conventional technology.

In order to achieve the abovementioned objective, the present invention proposes a pneumatic tool, which comprises a housing, a chamber defined by the housing, and a pneumatic mechanism disposed inside the chamber. The housing includes a gas inhale channel and a gas exhaust channel respectively interconnecting with the chamber. The present invention is characterized in that the pneumatic tool includes a cylinder disposed inside the chamber and a ventilation gap formed between the cylinder and the chamber and interconnecting with the gas exhaust channel. The cylinder includes a compartment for receiving the pneumatic mechanism, a gas inlet hole interconnecting with the compartment and the gas inhale channel, and at least one gas outlet hole interconnecting with the compartment and the ventilation gap. The pneumatic tool of the present invention further comprises at least one buffer turbulent channel disposed on at least one of one side of the cylinder, which faces the ventilation gap, and one side of the chamber, which faces the ventilation gap. In one embodiment, the pneumatic mechanism includes a pneumatic wheel driven to rotate by a high-pressure and high-speed gas and a transmission shaft axially coupled to the pneumatic wheel and extended to the exterior of the housing. Further, the pneumatic tool of the present invention includes a utility tool disposed in one end of the transmission shaft, which is far away from the housing.

In one embodiment, the transmission shaft includes an assembly member disposed in the exterior of the housing for assembling the utility tool; the axis of the utility tool and the axis of the transmission shaft are collinear.

In one embodiment, the transmission shaft includes an assembly member disposed in the exterior of the housing for assembling the utility tool; the axis of the utility tool and the axis of the transmission shaft are non-collinear.

In one embodiment, the cylinder includes an auxiliary turbulent channel neighboring the gas outlet hole and facing the ventilation gap.

In one embodiment, the pneumatic tool includes a weight block disposed in the transmission shaft to increase the torsion and rotation speed of the transmission shaft.

In one embodiment, the utility tool is a grinding wheel or a polishing wheel; the pneumatic tool includes a dust-proof hood surrounding the utility tool.

In comparison with the conventional technology, the present invention has the following characteristics: the pneumatic tool of the present invention comprises at least one buffer turbulent channel disposed on at least one of one side of the cylinder, which faces the ventilation gap, and one side of the chamber, which faces the ventilation gap; while the high-pressure and high-speed gas, which has been inside the ventilation gap but has not been exhausted from the gas exhaust channel, flows through the buffer turbulent channel, it will slow down because of the variation of the cross section area between the buffer turbulent channel and the ventilation gap; thus, the buffer turbulent channel can prevent the high-pressure and high-speed gas from flowing to the neighboring area of the gas outlet hole at too fast a speed lest the high-pressure and high-speed gas inside the compartment cannot be smooth exhausted from the gas outlet hole; therefore is overcome the problem that the high-pressure and high-speed gas cannot smooth drive a pneumatic device to rotate in the conventional technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically showing a pneumatic tool according to one embodiment of the present invention;

FIG. 2 is an exploded view schematically showing a pneumatic tool according to a first embodiment of the present invention;

FIG. 3 is a top sectional view schematically showing a pneumatic tool according to the first embodiment of the present invention;

FIG. 4 is a side sectional view schematically showing a pneumatic tool according to the first embodiment of the present invention;

FIG. 5 is a top sectional view schematically showing a local region of a pneumatic tool according to the first embodiment of the present invention;

FIG. 6 is a top sectional view schematically showing a local region of a pneumatic tool according to a second embodiment of the present invention; and

FIG. 7 is a top sectional view schematically showing a local region of a pneumatic tool according to a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The technical contents of the present invention will be described in detail in cooperation with drawings below.

Refer to FIGS. 1-5. The present invention proposes a pneumatic tool 1, which comprises a housing 11, a chamber 12 defined by the housing 11, a pneumatic mechanism 13 disposed inside the chamber 12, and a cylinder 14 disposed inside the chamber 12. The housing 11 includes a gas inhale channel 111, a gas exhaust channel 112, and an end plate 113. The gas inhale channel 111 and the gas exhaust channel 112 respectively interconnect with the chamber 12. The end plate 113 constrains the pneumatic mechanism 13 and the cylinder 14 inside the chamber 12. The pneumatic tool 1 may be a tool driven by a high-pressure and high-speed gas, such as a grinder or a sander. The pneumatic tool 1 includes a utility tool 15, such as a grinding wheel or a sanding wheel. The pneumatic mechanism 13 includes a pneumatic wheel 131 driven to rotate by a high-pressure and high-speed gas and a transmission shaft 132 axially coupled to the pneumatic wheel 131 and extended to the exterior of the housing 11 for the assemblage of the utility tool 15. Thereby, while the high-pressure and high-speed gas drives the pneumatic wheel 131 to rotate, the pneumatic wheel 131 can further drive the utility tool 15 to rotate via the transmission shaft 132.

A ventilation gap 16 is formed between the cylinder 14 and the chamber 12, interconnecting with the gas exhaust channel 112. The ventilation gap 16 is not only referred to the region neighboring a gas outlet hole 143 but also referred to the annulus-like space between the cylinder 14 and the chamber 12. The cylinder 14 includes a compartment 141 receiving the pneumatic mechanism 13, a gas inlet hole 142 interconnecting with the compartment 141 and the gas inhale channel 111, and at least one gas outlet hole 143 interconnecting with the compartment 141 and the ventilation gap 16. The pneumatic tool 1 also comprises at least one buffer turbulent channel 144/114 disposed on at least one of one side of the cylinder 14, which faces the ventilation gap 16, and one side of the chamber 12, which faces the ventilation gap 16. In other words, the pneumatic tool 1 may include at least one buffer turbulent channel 144 disposed on one side of the cylinder 14, which faces the ventilation gap 16 (as shown in FIG. 5) or at least one buffer turbulent channel 114 disposed on one side of the chamber 12, which faces the ventilation gap 16 (as shown in FIG. 6). Alternatively, the pneumatic tool 1 simultaneously includes at least one buffer turbulent channel 144 disposed on one side of the cylinder 14, which faces the ventilation gap 16, and at least one buffer turbulent channel 114 disposed on one side of the chamber 12, which faces the ventilation gap 16 (as shown in FIG. 7). Below, the embodiment wherein the pneumatic tool 1 includes at least one buffer turbulent channel 144 disposed on one side of the cylinder 14, which faces the ventilation gap 16, will be used to exemplify and demonstrate the present invention.

Refer to FIGS. 2-5. In application of the pneumatic tool 1, the gas inhale channel 111 is connected with an air compressor (not shown in the drawings). The air compressor inputs a high-pressure and high-speed gas into the gas inhale channel 111. The high-pressure and high-speed gas flows from the gas inhale channel 111 through the gas inlet hole 142 into the compartment 141 and drives the pneumatic wheel 131 to rotate. Then, the pneumatic wheel 131 further drives the utility tool 15 to rotate via the transmission shaft 132. Thus, the user can use the rotating utility tool 15 to undertake an operation (such as a grinding operation or a cutting operation) on an object (not shown in the drawings). After driving the pneumatic mechanism 13, the high-pressure and high-speed gas goes from the compartment 141 through the gas outlet hole 143 to the ventilation gap 16 and then exhausts from the ventilation gap 16 to the gas exhaust channel 112, whereby the high-pressure and high-speed gas supplied by the air compressor can be persistently input into the chamber 12 through the gas inhale channel 111 to drive the pneumatic mechanism 13 to rotate.

In the present invention, the pneumatic tool 1 includes at least one buffer turbulent channel 144/114 disposed on at least one of one side of the cylinder 14, which faces the ventilation gap 16, and one side of the chamber 12, which faces the ventilation gap 16. While the high-pressure and high-speed gas, which has been inside the ventilation gap 16 but has not yet exhausted from the gas exhaust channel 112, flows through the buffer turbulent channel 144/114, it will slow down because of the variation of the cross section area between the buffer turbulent channel 144/114 and the ventilation gap 16. Therefore, the buffer turbulent channel 144/114 can prevent the high-pressure and high-speed gas from flowing to the neighboring area of the gas outlet hole 143 at too fast a speed lest the high-pressure and high-speed gas inside the compartment 141 cannot exhaust from the gas outlet hole 143 smooth. Therefore, the present invention enables the high-pressure and high-speed gas to flow smooth in the gas inhale channel 111, the chamber 12, and the gas exhaust channel 112 to drive the pneumatic mechanism 13, whereby the pneumatic mechanism 13 can achieve higher speed and higher torsion to drive a larger-size utility tool 15, wherefore is overcome the problem that the high-pressure and high-speed gas cannot smooth drive a pneumatic device to rotate in the conventional technology.

In one embodiment, for further increasing the operational smoothness of the pneumatic mechanism 13, the cylinder 14 further includes an auxiliary turbulent channel 145 neighboring the gas outlet hole 143 and facing the ventilation gap 16. As shown in FIG. 2, the auxiliary turbulent channel 145 and the buffer turbulent channel 144 are respectively disposed at different locations. While the high-pressure and high-speed gas flows from the gas outlet hole 143 to the auxiliary turbulent channel 145, it will slow down because of the variation of the cross section area between the auxiliary turbulent channel 145 and the gas outlet hole 143. Therefore, the auxiliary turbulent channel 145 can prevent the high-pressure and high-speed gas inside the compartment 141 from flowing to the gas exhaust channel 112 at too fast a speed and interfering with the high-pressure and high-speed gas inside the ventilation gap 16. Therefore, the present invention enables the high-pressure and high-speed gas to flow smooth in the gas inhale channel 111, the chamber 12, and the gas exhaust channel 112 to drive the pneumatic mechanism 13. In addition to the abovementioned buffer turbulent channel 144 and auxiliary turbulent channel 145 formed on the surface of the cylinder 14, an arbitrary position on the surface of the cylinder 14 can be recessed to form at least one another turbulent channel (such as another buffer turbulent channel 144 or another auxiliary turbulent channel 145) if the overall thickness of the cylinder 14 is not decreased. Thereby, the flowing speed of the high-pressure and high-speed gas can be regulated inside the chamber 12 with the cylinder 14 being maintained at a given structural strength. Then, the high-pressure and high-speed gas can go smooth from the gas inhale channel 111 into the chamber 12 to drive the pneumatic mechanism 13 and optimize the rotation speed of the pneumatic_mechanism 13. It should be noted: the buffer turbulent channel 144/114 formed on the cylinder 14 or chamber 12 of the pneumatic tool 1 is not limited to a groove recessed on the cylinder 14 or chamber 12; the buffer turbulent channel 144/114 may also be in form of a turbulent plate disposed on the cylinder 14 or chamber 12 (not shown in the drawings). In other words, it is sufficient for the present invention to form at least one structure, which can generate a level drop and vary the cross section area to decrease the flowing speed of the high-pressure and high-speed gas.

Refer to FIG. 2. In one embodiment, for increasing the rotation speed of the pneumatic mechanism 13, a weight block 17 is disposed in the transmission shaft 132. While the pneumatic wheel 131 drives the transmission shaft 132, the centrifugal force generated by the rotating weight block 17 can increase the speed and torsion for driving the utility tool 15.

From the above description, it is leaned clearly that the pneumatic tool 1 of the present invention is a tool driven by a high-pressure and high-speed gas. As shown in FIG. 1 and FIG. 2, the utility tool 15 is a grinding wheel (disc) or a polishing wheel (disc). In one embodiment, the pneumatic tool 1 further comprises a dust-proof hood 18, which surrounds the utility tool 15 and prevents the dust generated by the pneumatic tool 1 from entering the chamber 12 or irritating the eyes of the user. In one embodiment, the transmission shaft 132 further includes an assembly member 133 disposed in the exterior of the housing 11 for assembling the utility tool 15, as shown in FIG. 2. In one embodiment, the assembly member 133 is an eccentric axial seat; after the utility tool 15 is assembled to the assembly member 133, the axis of the utility tool 15 is non-collinear with respect to the axis of the transmission shaft 132; thus, the centrifugal force of the rotating utility tool 15 can increase the rotation speed of the transmission shaft 132. In one embodiment, the assembly member 133 is an axial seat; after the utility tool 15 is assembled to the assembly member 133, the axis of the utility tool 15 is collinear with the axis of the transmission shaft 132; thus is increased the stability of the rotation of the transmission shaft 132. 

What is claimed is:
 1. A pneumatic tool comprising a housing, a chamber defined by the housing, and a pneumatic mechanism disposed inside the chamber, wherein the housing includes a gas inhale channel and a gas exhaust channel respectively interconnecting with the chamber, and wherein the pneumatic tool is characterized in that the pneumatic tool comprises a cylinder disposed inside the chamber and a ventilation gap formed between the cylinder and the chamber and interconnecting with the gas exhaust channel, and that the cylinder includes a compartment receiving the pneumatic mechanism, a gas inlet hole interconnecting with the compartment and the gas inhale channel, and at least one gas outlet hole interconnecting with the compartment and the ventilation gap, and that the pneumatic tool also comprises at least one buffer turbulent channel disposed on at least one of one side of the cylinder, which faces the ventilation gap, and one side of the chamber, which faces the ventilation gap.
 2. The pneumatic tool according to claim 1, wherein the pneumatic mechanism includes a pneumatic wheel driven to rotate by a high-pressure and high-speed gas and a transmission shaft axially coupled to the pneumatic wheel and extended to the exterior of the housing.
 3. The pneumatic tool according to claim 2 further comprising a utility tool installed at one side of the transmission shaft, which is far away from the housing.
 4. The pneumatic tool according to claim 3, wherein the transmission shaft includes an assembly member disposed in the exterior of the housing for assembling the utility tool; the axis of the utility tool and the axis of the transmission shaft are collinear.
 5. The pneumatic tool according to claim 3, wherein the transmission shaft includes an assembly member disposed in the exterior of the housing for assembling the utility tool; the axis of the utility tool and the axis of the transmission shaft are non-collinear.
 6. The pneumatic tool according to claim 1, wherein the cylinder further includes an auxiliary turbulent channel neighboring the gas outlet hole and facing the ventilation gap.
 7. The pneumatic tool according to claim 2 further comprising a weight block disposed in the transmission shaft to increase the rotation speed and torsion of the overall transmission shaft.
 8. The pneumatic tool according to claim 3, wherein the utility tool is a grinding wheel or a polishing wheel.
 9. The pneumatic tool according to claim 8 further comprising a dust-proof hood surrounding the utility tool. 